Layers are a way of managing, tidying and also controlling
the visual layout of a drawing. A whole section of a drawing
can be turned on or off, or simply one aspect can be controlled
- text for example. This is all done by using layers within
concept of layers is used in other software applications,
such as Paintshop programs. For those not aware of the concept,
we'll start from the beginning:
a new Autocad drawing is created, everything which is drawn
is drawn on the one default layer, named 0. When creating
drawings, the layer 0 shouldn't really be used. New layers
should be set up with names corresponding to the content
contained on them.
is a layer?
A layer can be thought
of as a large piece of clear plastic, as infinitely large
as the drawing area in Autocad. When drawing in Autocad,
everything is drawn on the default layer which is set current.
Only the objects you are drawing are visible on the layer,
the layer itself can never be seen - it is invisible. Each
new layer is created by you, the user .Normally, it is acceptable
to have a layer for each different part of a drawing. The
layers created for a simple house plan could be as follows:
The separate lines and
shapes representing each part of the house would be arranged
on its relevant layer above. Each layer could be assigned
its own colour so that everything drawn on that layer appeared
the same colour.
Remember we said that layers can be used to manage drawings?
well for example, in order to see the drawing more clearly,
we may want to remove all the text and dimensions from the
drawing. We want to keep the information, just remove it
from view. Deleting it wouldn't be appropriate as we would
lose all of our work! All we have to do is tell Autocad
to not display the Text_Notes
and Dimensions layers by turning
off the layers in layer manager. The layers can then ne
turned back on again whenever we choose.
are controlled by the layer properties
which is located on the object properties toolbar:
The layer property manager is where all the layers are
controlled. The layout above shows a typical use of layers.
the layer property manager we can:
Add a New Layer - Press the New
button to create a new layer.
Delete a Layer - Press the delete
button to delete the selected layer.
Set Current layer - Press the current
button to set the selected layer current. All objects
drawn will then be drawn on this current layer.
Show Details - Press the show
details button to see more detailed information
about the selected layer.
Each layer also has the following options against it:
Name - Displays the layer
On - Controls if the layer
is on or off. Select the light bulb to turn the layer off
on the drawing.
Freeze in all VP - Pressing
this will freeze the layer in all viewports as well as the
current model view (see lesson 10 to learn about viewports)
Lock - This handy feature
locks a layer preventing any content of the layer from being
Colour - Change this to
whichever colour you like. All objects drawn on the layer
will display the chosen colour provided that the objects
colour setting in the object properties toolbar (shown above)
is set to 'By Layer'.
Linetype - Set the default
linetype for all objects drawn on the layer. i.e continuous,
dashed, dotted etc.
- Set the thickness a line appears .Default is no thickness.
This option can be toggled on/off on the display by the
LWT button above the command console.
Plot - Select
if the layer will be shown when the drawing is plotted (printed).
current layer, layer colour, linetype and lineweight can
all be controlled outside of the layer properties manager
via the object properties toolbar.
That's it for basic layer controls! Get used to using layers
as you will be using them often - especially when you find
you need to start managing large drawing files that contain
a lot of information.
any errors/omissions to
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